Ceramic material, compositions and methods for manufacture thereof

Abstract

The present invention relates to a method of producing a ceramic material comprising the steps of: a) mixing a first clay composition comprising silica and a silicate mineral with a second clay composition; and b) firing the mixed clay composition from step a) to form a ceramic product. The present invention also relates to an engobe clay composition, sanitary ware and methods of productions thereof.

Description

TECHNICAL FIELD [0001] The present invention relates to a ceramic material, a clay composition and processes for manufacture or preparation thereof. In particular, the present invention relates to a ceramic material made from the firing of clay products, a clay composition and processes for manufacture or preparation thereof. The present invention also relates to an engobe clay composition for application on a clay body before glazing and firing. One application of the ceramic material, clay composition, engobe clay composition and processes and applications therefor is in the manufacture of sanitary ware such as toilet bowls, kitchen bowls, bath tubs, wash basins, kitchen sinks, slabs, vanity bowls and the like. BACKGROUND OF THE INVENTION [0002] Consumer interest in the use of ceramics has resulted in a demand for intricate large sanitary ware items such as toilet bowls, kitchen sinks, slabs, vanity,bowls and the like which are made of a ceramic material. Previously, a ceramic bod...

AI Technical Summary

Benefits of technology

[0105] Wollastonite may be added to the engobe composition in an amount ranging from about 0.5 to about 20 wt %, or about 1.0 to about 19 wt %, about 1.5 to about 18 wt %, about 2.0 to about 17 wt %, about 2.5 to about 16 wt %, about 3.0 to about 15 wt %, about 3.5 to about 14 wt %, about 4.0 to about 13 wt %, about 4.5 to about 12 wt %, 5.0 to about 11 wt %, about 5.5 to about 10 wt %, about 5.5 to about 9 wt %, about 6 to about 8 wt %, and about 7 wt %. Wollastonite may be in the form of acicular wollastonite. The presence of wollastonite may provide improved dimensional stability green strength and may reduce the cracking and chipping of the engobe composition. Also, the addition of wollastonite in the engobe composition may substantially eliminate or at least reduce the spangling defect and provides the fire clay ware with excellent glaze appearance.

[0108] The engobe composition of the present invention may comprise zirconium silicate (ZrSiO4) or tin oxide. The presence of zirconium silicate (zircon) or tin oxide provides the engobe composition with the desired whiteness and improves the abrasion and mechanical resistance.

[0114] In one example of the engobe composition, the lithium-containing mineral is spodumene which may be selected from one or both of the two varieties called Kunzite and Hiddenite. The presence of lithium-containing mineral aluminum silicate (spodumene) may provide the engobe composition of the present invention with an excellent thermal shock resistance and may lessen the incident of cooling cracks (dunts).

[0149] The engobe composition, may range in color (for example from red to buff) may be applied between the ceramic body and the glaze layer. The engobe composition is typically classified between a glaze and a clay. Although the engobe composition fires more vitreous than the ceramic body it covers, the engobe composition does not become glassy like a glaze during firing. One of the benefits of using an engobe is that it can be applied over a wet or dry clay body, and then fired to the clay's specified temperature. Engobes can be painted, brushed, sprayed and layered. An engobe in a stiffer form can be used to add texture, and after the piece is fired, a stain wash can be applied to highlight the surface.

Problems solved by technology

However, the manufacture of intricate, large sanitary ware items using vitreous china is difficult since vitreous china has double the firing contraction rate of a fire clay body and also suffers from the problem of significant sagging during the firing of this material to a glassy state.

A disadvantage with the known engobe composition is that the properties of thermal shock resistance, good glaze appearance and chemical resistance are poor for fired clay products and particularly for fired sanitary ware products.